It is studied that a polymerized film, e.g., a polymer thin film represented by a polyimide thin film, is used as an interlayer insulating film of a semiconductor integrated circuit device or a liquid crystal alignment film of a flat panel display, e.g., a liquid crystal display device.
Polyimide is divided into aromatic polyimide and non-aromatic polyimide depending on the structure thereof. Non-aromatic polyimide has an advantage in that non-aromatic polyimide is lower in relative dielectric constant than aromatic polyimide and in that non-aromatic polyimide makes it possible to obtain a transparent film.
Non-aromatic polyimide provides an advantage absent in aromatic polyimide in that (a) a film having a low dielectric constant is obtainable and (b) a transparent film is obtainable. On the other hand, non-aromatic polyimide is inferior in heat resistance to aromatic polyimide.